ABSTRACT

Temperature influences fish’s susceptibility to infectious disease through an immune response. However, the mechanism underlying this regulation is yet to be elucidated. In this study, we compared the susceptibility of crucian carp that were grown at 18°C and 33°C, respectively, to Aeromonas sobrial infection and found that crucian carp was more susceptible when grown at 33°C. These distinct susceptibilities of fish at different temperatures to infection may partially be explained by their differences in the metabolism as revealed by comparative metabolomics profiling: crucian carp demonstrated enhanced TCA cycle but reduced fatty acid biosynthesis; Our study also found that maltose was the most suppressed metabolite in fish grown at 33°C. Importantly, exogenous injection of maltose enhances crucian carp survival grown at 33°C by 30%. Further study showed that exogenous maltose downregulated the production of several cytokines but enhanced the lysozyme (lyz) and complement component c3, which involves the humoral innate immunity. Our results suggest that maltose promotes the survival of crucian carp likely through fine tuning the immune gene expression, and this finding provides a novel approach to manage bacterial infection.

摘要

温度通过免疫反应影响鱼类对传染病的敏感性。但是，尚待阐明该法规的基础机制。在这项研究中，我们比较了分别在18°C和33°C下生长的cru鱼对气单胞菌的敏感性。感染，发现cru鱼在33°C下生长时更容易受到感染。比较代谢组学分析表明，鱼在不同温度下对感染的不同敏感性可能部分是由于它们在新陈代谢上的差异而引起的：:鱼表现出增强的TCA循环，但脂肪酸生物合成减少；我们的研究还发现，麦芽糖是在33°C下生长的鱼类中抑制程度最高的代谢产物。重要的是，外源注射麦芽糖可使cru鱼在33°C时的存活率提高30％。进一步的研究表明，外源麦芽糖下调了几种细胞因子的产生，但增强了溶菌酶（lyz）和补体成分c3，涉及体液先天免疫。我们的结果表明，麦芽糖可能通过微调免疫基因的表达来促进cru鱼的生存，而这一发现为处理细菌感染提供了一种新颖的方法。